Commit ec89a06f authored Dec 09, 2009 by Xiao Guangrong Committed by Ingo Molnar Dec 09, 2009

perf_event: Cleanup for cpu_clock_perf_event_update()



Using atomic64_xchg() instead of atomic64_read() and
atomic64_set().

Signed-off-by: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
Reviewed-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Paul Mackerras <paulus@samba.org>
LKML-Reference: <4B1F19DC.90204@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

parent b93f7978

kernel/perf_event.c

+1 −2

Original line number	Diff line number	Diff line
		@@ -4079,8 +4079,7 @@ static void cpu_clock_perf_event_update(struct perf_event *event)
		u64 now;

		now = cpu_clock(cpu);
		prev = atomic64_read(&event->hw.prev_count);
		atomic64_set(&event->hw.prev_count, now);
		prev = atomic64_xchg(&event->hw.prev_count, now);
		atomic64_add(now - prev, &event->count);
		}